Hole drill and debris clearance method and means

ABSTRACT

In a method and means of rock fracturing and excavating holes using a cannon to fire hypervelocity projectiles at the rock, the debris created in the course of such excavation is removed by releasing the propellant gases created in the firing of the projectiles in the hole in a manner to blow the debris out of the hole.

` UnitedStates Patent 1191 y 1111 '3,863,723

Godfrey l [45] Feb..4, 1975 [54] HOLE DRILL ND DEBRIS CLEARANCE 2,544,573 3/1951 Vincent l75/4.5 METHQD AND MEANS 2,923,204 2/1960 175/458 X l 3,104,584 9/1963 102/22 X [75l Inventor: lCharles S- Godfrey, Berkeley, Callf. 3,232,168 2/1966 175/457 x 3,511,538 5/1970 Guenter 175/3.5 x [73] ASSgnee- {hyss MHI''MMI Company sa 3,695,715 10/1972 Godfrey 175/4.5 X ea o a- 3,721,471 3/1973 Bergmann et a1 299/13 x [22] Filed: Jan. 23, 1974 Primary Examiner- David H. Brown [21] Appl' No" 435632 Attorney, Agent, or Firm-Lindenberg, Freilich,

. Wasserman, Rosen & Fernandez [52] U.S. Cl l75/4.5, 102/22, 17574.57, 299/13 [51] Int. Cl.. E21b 7/00, E2lb 19/00 [57] ABSTRACT [58] Field 0f Search 175/2, 3.5, 4.5, 4.53, 4.57, In a method and means 0f rock fraeturing and excel75/4.458; 299/13, 18; 89/7; 10g/22, 23, 25 vatng holes using a cannon to fire hypervelocity proi jectiles at the rock, the debris created in the course of such excavation is removed by releasing the propellant [56] References Cited gases created in the tiring of the projectiles in the hole in a manner t0 blOW the debris Out Of the hole.

1,585,664 5/1926 Gilman 175/2 X 7 Claims, 3 Drawing Figures 1` HOLE DRILL AND DERIs CLEARANCE METHOD I AND MEANS BACKGROUND oF THE INVENTION This invention relates to a method and means for re moving debris from a hole created by firing hypervelocity projectiles into the hole.

In a U.S. Pat. No. 3,695,715 there is described a rock fracturing apparatus wherein projectiles formed, for example, from concrete with a plastic casing, are tired at the rock wherein a hole is desired to be made. Propellant gases such as a mixture of a carbonaceous gas and oxygen-may be used as a propellant.

In the useof this technique for the rapid excavation of tunnels in rock, it has been noted that the diameter of a hole that is made using this technique has always been much larger than the projectile which is used to dig the hole as well as the diameter ofthe gun. For example, in using a smooth bore 90-mm gun using an 8 l/z pound concrete projectile impacting granite at 5,000 feet per second, a hole diameter of I6 inches, i.e., 406- mm, is obtained. A second fact that has been noted is that the debris in the hole is a finely pulverized powder with few pieces of any size.

In order to continue drilling, it is necessary to remove the debris created as a result ofthe drilling. This usually means discontinuing the drilling, moving the drilling equipment away from the hole to enable the debris in the hole to be cleared and then bringing the drilling equipment back.

The time required for debris removal, as well as the labor required, constituted a loss in time as well as wages. lf some arrangement could be found for debris removal without interrupting the drilling process then obviously, these losses can be avoided.

OBJECTS AND SUMMARY OF THE INVENTION An object of this invention is to provide a novel method and means of debris removal in a rock excavating system ofthe type described.

Yet, another object of the present invention is a novel method and means of debris removal in a system ofthe type described without interruption to the drilling process.

These and other objects of the invention may be achieved in a roc'k drilling system using a gun which hurls a projectile at the rock. By directing the projectile fired by the gun at or near the bottom of the hole created by previously fired projectiles, the impacting projectile stirs up the powder and particles which are in the hole when it impacts. The propellant gases which are generated to hurl the projectile are directed into the hole and released near the bottom. These gases sweep up the powder and particles and direct them up an annular space formed between the extensions ofthe gun barrel used to confine and guide the propellant gases and the wall ofthe hole. As the hole is made deeper, further gun barrel extensions are added to guide and confine the propellant gases until they are released near the bottom ofthe hole.

The novel features ofthe invention are set forth with particularity in the appended claims. The invention will best be understood from the following description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a schematic illustration of an embodiment of the invention.

FIG. 2 schematically illustrates how the projectile and propellant gases of a gun may be directed into the bottom of deep holes.

FIG. 3 schematically illustrates another embodiment of the invention.

DESCRIPTION OF THE EMBODIMENT OF THE INVENTION In U.S. Pat. No. 3,695,715, which describes a rock fracturing technique using a cannon to fire a frangible projectile at the rock to be fractured, a system is described in FIGS. I and 2 for suspending a derrick over a predrilled pilot hole. The derrick supports a platform which carries two guns. The guns are fired automatically at preprogrammed intervals at certain aiming lo cations. The platform may be lowered by means of Winches into the hole as it is enlarged. At the bottom ofthe hole a sweep feeder is rotated around the column and an auger gathers the rubble which is swept up into the column where a vertical bucket line brings the rubble up to the top of the hole. Another variation of the system shows a self propelled vehicle which can be driven to a desired distance from the face of a horizontal tunnel being excavated.

The present invention relies on the fact that the propellant gases, which propel the projectile used for rock fracturing, have sufficient energy to lift the debris created by the impact of the projectile, out of the hole. However, if the size of the hole being drilled is such that the gases emitted from the muzzle of the gun can expand and dissipate the energy that they have by the time the propellant gas can reach the bottom of the hole then, obviously, the debris cannot be lifted out of the hole.

Such is the case with the systems as shown and described in U.S. Pat.No. 3,695,715. The silo or hole which is being drilled utilizing the two guns supported on a platform as shown in FIG. 2, and the tunnel into which the self propelled gun shown in FIG. 8 can be driven, is far too large, so that any propellant gas emitted by either of the guns expands in a substantially unconfined area to dissipate its energy.

Referring now to FIG. l, there is shown a schematic arrangement of an embodiment of this invention. A pair of derricks, respectively l0, l2, support a cannon 14, with the end of its barrel 16, within a few feet from the bottom 18 of a hole in the earth 20. This distanceA is not critical. This cannon 14 may be operated in the manner described in U.S. Pat. No. 3,695,715 using projectiles and propellant gases of the type described therein. However, the diameter ofthe hole into which the barrel ofthe cannon is extended, is that created by the firing of the cannon. In other words, the size ofthe hole into which the gun is fired is such that the energy of the propellant gases which are emitted from the muzzle of the gun, when the gas impacts upon the bottom of the hole, is substantially undissipated in the distance between the muzzle ofthe gun and the bottom of the hole. vAs a result, the powdered material created by the impacting projectile is carried up the hole around the barrel of the gun until this debris strikes a deflector 22, which surrounds the top ofthe hole around the gun, and of which only a portion is shown. The deflector deflects the powdered material either onto the ground around the hole or into some suitable container.

lt was previously pointed out that a 90-mm cannon firing an 8 V2 pound concrete projectile created hole diameters on the order of I6 inches. A 15S-mm gun firing a 43.5 pound concrete projectile can form a 34 inch diameter hole at a penetration rate of l7 inches per shot. Again, the debris created is highly pulverized and readily elevated to a height of a couple of hundred feet. being carried upward by the propellant gases.

FIG. 2 schematically represents a preferred arrangement, wherein the gun barrel has extensions added thereto so that the propellant gases are confined and guided and are emitted until they are close to the region where the debris is created by the impacting projectile. The gun, 30, has a sleeve, 32, fitted around the barrel. The gun may be supported by derricks as previously shown in FIG. l, or may have a rack and gear arrangement, 34, 36, whereby it may be raised and lowered some suitable distance above the ground, such as 8 feet. The debris shield, 38, is also shown in place.

At the end of the sleeve adjacent to the gun muzzle, a quick connect joint, 40, is placed. This is a type of joint which is well known in the oil drilling art where casings are connected at their ends to provide a long drill string into the hole. A plurality of extension sections, respectively, 42, 44, 46, are shown connected end wise to one another, in the manner in which the casings or pipes are connected together to form a drill string in an oil well. Each time it is desired to connect a new section of casing, the gun and the extensions on its barrel are elevated until it is high enough above the hole to enable the next casing section to be connected in place.

Also shown schematically, is a structure known as a gripper," 50, which serves the function of holding a new extension section in place until the last of the extensions previously connected to the gun barrel can be lowered onto it. The gripper, which'is also well known in the oil drilling art, may merely consist of an arrangement for extending a couple of gripping posts to hold a section in place, until it is joined to the remaining sections. The gripper is then actuated to release the section so that the gun and its extensions may be lowered into the hole to position the opening in the last of the extensions adjacent the debris 52, at the bottom ofthe hole.

In the foregoing description, it will be appreciated that the propellant gas is not dissipated in a long hole but is kept substantially confined so that there is not too great a loss in energy until the gases impact the debris, which is already elevated to a certain extent as a result of the impact of the projectile. This places the debris in an ideal state for being carried up the hole by the flow of the gases. The diameter of the extensions is made slightly larger than the gun barrel. The extensions are not used for guiding the projectile and are not touched by the projectile. Their function is solely to confine and guide the propellant gases until they are released.

FIG. 3 is a fragmented schematic arrangement of another embodiment ofthe invention. When the diameter of a hole is so large that the propellant gases from a single gun cannot effectively clear debris from the bottom ofthe hole, a multiplicity of guns 50, 52, 54, 56 may be used. These are fired simultaneously with the result that a sufficient amount of the propellant gases is produced within the confines of the hole to cause the debris to rise out of the hole. Extension sections may be added to the cluster of gun barrels in the same manner as was described for a single gun barrel. An extension section may be fitted around each of the gun barrels in the cluster, or a single extension cylinder may be fitted around the entire cluster.

It should be noted that while the invention has been described and shown as being used for a vertical hole, it should be obvious that this invention is also applicable for removing debris from holes having other orientations as well.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. In a system wherein a hole is excavated using a cannon which fires a frangible projectile by means of propellant gases into said hole, the method of removing debris from the bottom of said hole, comprising emitting gases including propellant gases from said cannon near to the bottom of said hole whereby said gases carry the debris upward out of said hole through the annular space between the walls of said hole and the barrel of said cannon.

2. In a system as recited in claim l wherein said step of emitting gases including propellant gases near to the bottom of said hole includes the step of adding extensions to the barrel of said cannon as said hole gets deeper to maintain said propellant gases substantially confined until they are emitted adjacent to the bottom of said hole. Y

3. A method of excavating a hole in rock and removing debris from said hole comprising projecting toward the bottom of said hole a frangible projectile with propellant gases from a cannon, confining said propellant gases until they are emitted near to the bottom of said hole. 4. A method as recited in claim 3 wherein said step of confining said propellant gases until they are emitted near to the bottom of said hole includes adding extensions to the barrel of said cannon as said hole gets deeper to maintain said propellant gases confined until they are emitted adjacent the bottom of said hole.

5. A method as recited in claim 3, wherein said cannon, from which said frangible projectile is projected with propellant gases, comprises a multiplicity of cannons simultaneously projecting frangible projectiles with propellant gases.

6. In a system for excavating a hole in rock wherein a cannon fires a frangible projectile by means of propellant gases into said hole, means for removing debris from the bottom of said hole, comprising means for supporting said cannon with the end of its barrel aimed at the bottom of said hole for emitting propellant gases at said bottom of said hole, and

means for lengthening the barrel of said cannon as said hole gets deeper to keep said propellant gases confined until they are emitted near the bottom of said hole.

7. A method of excavating a hole in rock and removing debris from said hole comprises loading a plurality of cannons with a plurality of frangible projectiles and propellant powder,

aiming said plurality of cannons at the bottom of said hole,

simultaneously firing said plurality of cannons to propel said plurality of projectiles with propellant gases at the bottom of said hole, and

confining said propellant gases until they are emitted 

1. In a system wherein a hole is excavated using a cannon which fires a frangible projectile by means of propellant gases into said hole, the method of removing debris from the bottom of said hole, comprising emitting gases including propellant gases from said cannon near to the bottom of said hole whereby said gases carry the debris upward out of said hole through the annular space between the walls of said hole and the barrel of said cannon.
 2. In a system as recited in claim 1 wherein said step of emitting gases including propellant gases near to the bottom of said hole includes the step of adding extensions to the barrel of said cannon as said hole gets deeper to maintain said propellant gases substantially confined until they are emitted adjacent to the bottom of said hole.
 3. A method of excavating a hole in rock and removing debris from said hole comprising projecting toward the bottom of said hole a frangible projectile with propellant gases from a cannon, confining said propellant gases until they are emitted near to the bottom of said hole.
 4. A method as recited in claim 3 wherein said step of confining said propellant gases until they are emitted near to the bottom of said hole includes adding extensions to the barrel of said cannon as said hole gets deeper to maintain said propellant gases confined until they are emitted adjacent the bottom of said hole.
 5. A method as recited in claim 3, wherein said cannon, from which said frangible projectile is projected with propellant gases, comprises a multiplicity of cannons simultaneously projecting frangible projectiles with propellant gases.
 6. In a system for excavating a hole in rock wherein a cannon fires a frangible projectile by means of propellant gases into said hole, means for removing debris from the bottom of said hole, comprising means for supporting said cannon with the end of its barrel aimed at the bottom of said hole for emitting propellant gases at said bottom of said hole, and means for lengthening the barrel of said cannon as said hole gets deeper to keep said propellant gases confined until they are emitted near the bottom of said hole.
 7. A method of excavating a hole in rock and removing debris from said hole comprises loading a plurality of cannons with a plurality of frangible projectiles and propellant powder, aiming said plurality of cannons at the bottom of said hole, simultaneously firing said plurality of cannons to propel said plurality of projectiles with propellant gases at the bottom of said hole, and confining said propellant gases until they are emitted near the bottom of said hole. 